PDF Guides
Compressing Tax Documents for CRA Upload
Filing your return through NETFILE-certified software doesn't usually involve attaching documents. But if the CRA reviews your return and specifically requests supporting documents — receipts, statements, or other records — you can submit them electronically through CRA My Account or Represent a Client, and there are real limits on what you can upload.
By GaryLast updated 3 min read
When this applies
This covers the "Submit documents online" feature in CRA My Account, used specifically when the CRA has requested supporting documentation — for example during a post-assessment review. It isn't part of filing your return itself.
What the CRA accepts
According to CRA's own guidance, accepted file formats include .pdf, .doc, .docx, .xls, .xlsx, .rtf, .txt, .jpg, .jpeg, .tiff, and .xps. The combined size of everything you submit in one go cannot exceed 150MB, and each file needs a unique, clear name.
How to prepare your documents
For a typical set of scanned receipts or statements, a few steps keep you well under the limit.
- Scan or photograph each document clearly
- Combine related pages (like a multi-page bank statement) into a single PDF rather than many separate image files
- Compress the combined PDF if it's still large, then zoom in to confirm the amounts and dates are still easy to read
- Give each file a clear name describing what it is, since the CRA reviewer needs to tell your documents apart
Start from the CRA letter
A review starts with a letter, either on paper or in your My Account mail. The letter names the claim being checked, lists what the CRA wants to see, gives a reference number and sets a date to reply by. Build your upload around that list. Send what is asked for and nothing else: extra pages slow the reviewer down and can raise new questions.
Keep the letter open while you prepare the files. The online service asks for the reference number so that your documents are matched to the right review.
One PDF per item on the list
The 150MB total is generous, so size is rarely the real problem. Order is. A reviewer who receives forty loose phone photos has to work out which receipt belongs to which claim. A reviewer who receives five named PDFs can check them against the letter in minutes.
- Sort the paper into piles that match the items in the letter, for example medical expenses, donations and tuition.
- Photograph or scan each pile in date order. Scan to PDF turns phone photos into pages, and JPG to PDF does the same for photos you have already taken.
- Make one PDF per pile. If you scanned in several sessions, join the parts with Merge PDF and drag the pages into date order.
- Name each file for what it holds and the tax year, such as 2025-medical-receipts.pdf. The CRA asks for unique, clear names.
- Open every file once and check that no receipt is cut off, upside down or hidden under another.
Receipts are small and fade
Till receipts are printed on thermal paper, which fades. Photograph them soon, on a dark surface, several to a page if they are small, with a gap between them. Pharmacy and medical receipts must show the date, the amount, what was paid for and who it was for, so check those four things are visible on each one.
Scan to PDF places photos on the page as you took them. It does not crop to the edge of the paper or straighten a tilted shot, so hold the phone directly above the receipt. If a page ends up sideways, fix it with Rotate PDF before you merge.
Do you need to compress at all?
Usually not. A hundred phone-photo pages can approach the limit, but a typical review bundle is far smaller. If you do need to shrink a file, use the Balanced level and look at the smallest print afterwards. Compressing redraws each page as an image, so leave downloaded slips and statements, which are already compact, as they are.
After you submit
Save the confirmation number the CRA shows you, and keep the exact files you sent in a folder named for the tax year. The CRA expects you to keep supporting records for six years, and having the same bundle on hand makes a follow-up question quick to answer.
Portal file size limits
Every figure below comes from the official page linked next to it. Portals change their limits, so confirm on the portal before you submit.
| Portal | Document | Limit | Source |
|---|---|---|---|
| CRA My Account: Submit documents | All files in one submission | 150 MB total (a limit of 10 files may apply) | CRA: Submit documents (My Account) |
- CRA: Submit documents (My Account): checked
Frequently asked questions
Is this the same as filing my tax return?
No. This is for submitting supporting documents when the CRA specifically requests them, separate from filing your return through certified tax software.
What's the maximum file size?
Per the CRA's published guidance, the total size of all documents submitted together cannot exceed 150MB.
Is my document uploaded to a server when I compress or merge it here?
No. Both tools run entirely in your browser, so your file never leaves your device before you submit it to the CRA yourself.
Can I send photos instead of PDFs?
The CRA's list of accepted formats includes .jpg, so photos are allowed. A single PDF per group of receipts is easier for the reviewer to follow than many separate images, and each file still needs a clear, unique name.
Should I black out other details on a statement?
Send what the letter asks for. If a bank statement shows unrelated transactions and you are unsure whether to hide them, ask the CRA using the contact details on the letter before you edit anything.